Dual cylinder brake



Aug' 9, 1966 E. K. DoMBEcK 3,265,164

DUAL CYLINDER BRAKE Original Filed Oct. 27, 1964 2 Sheets-Sheet 1 /6 I'jf I /3 56 36 /3 f n n if. l/ O 64 O 2, .tl .u 'i' l u: G o; f3," C@ @D:.1 ".'I /Z \\O C /2 jfl' 0 A I O s &" l:

IN VENTOR.

EDWD K. DOMBECK.

Mam

llg- 9, 1966 E. K. DoMBEcK 3,265,164

DUAL CYLINDER BRAKE Original Filed Oct. 27. 1964 2 Sheets-Sheet 2 :HIE EINVENTOR.

EDWARD K. DOMBECK 14 TTRNEY.

United States Patent O 3,265,164 DUAL CYLTNDER BRAKE Edward lli.Dombeck, South Bend, Ind., assigner t9 The Bendix Corporation, SouthBend, lud., a corporation of Delaware Original application Oct. 27,1964, Ser. No. 406,929.

Divided and this application Oct. 6, 1965, Sera 2 Claims. (Cl. 18S-152)This application is a division of my copending application Serial No.406,929, filed on October 27, 1964, which in turn is acontinuation-in-part of application Serial No. 210,768 (now abandoned).

This invention relates to a drum brake and more particularly to a drumbrake for use on a vehicle having a small wheel base diameter andrequiring a large braking force for stopping the vehicle.

One of the objects of this invention is to provide a brake having a setof brake shoes slidably mounted on each side of a backing plate.

Another object of this invention is to provide a brake with a wheelcylinder mounted on each face of a backing plate wherein the fluidchambers of each wheel cylinder are interconnected with each other.

A still further object of the invention is to accomplish the aboveobjects with the utilization of as many standard parts as possible.

Other objects and features of the invention will become apparent from aconsideration of the following description wherein a selected exampleembodiment has been chosen to illustrate the invention. The descriptionproceeds with a reference to the accompanying drawing wherein:

FIGURE 1 illustrates a front elevational view of a brake assembly of theinvention; and

FIGURE 2 is a view taken along section line 2 2 of FlGURE 1. i

Referring to FIGURES 1 and 2, a backing plate 10 is provided which maybe attached to a stationary part of a vehicle, for instance, a spindle(not shown). A pair of T-shaped brake shoes 12, 12a are slidably mountedon one face of the backing plate lil and a pair of brake shoes 14, 14aare slidably mounted on the other face of the backing plate 1li and arelocated directly behind the rst set of brake shoes. Each brake shoe hasa friction lining 13 attached to their rims 16 for frictionally engaginga brake drum 18. An adjustable strut 2@ is located between andinterconnects one set of adjacent ends of the brake shoes of each setand a spring 22 holds the ends of the brake shoes in engagement with theadjustable strut 20. An anchor pin 24 is secured to the backing plateand located between the other adjacent ends of each pair of brake shoesat each set for anchoring abutment thereof. A retainer plate 11 isprovided to laterally locate the ends of each pair of brake shoes withrespect to the anchor pin 24.

A wheel cylinder `26 is provided on one side of the backing plate foractuating the set of brake shoes 12, 12a and a wheel cylinder 28 isprovided on the other face of the backing plate for actuating the otherset of brake shoes 14, 14a. Each wheel cylinder has an ear 30 and flange32 each having an opening therein. The anchor pin 24 extends through theopening of the ears 30 with the nuts 34 pressing the ears intoengagement with a back- 3,265,164 Patented August 9, 1966 ice ing plate.A bolt and nut assembly 36 extends through the openings in the flanges32 for pressing the flanges into engagement `with the backing platethereby resulting in fixing the wheel cylinders to the backing plate.The wheel cylinder 26 has a boss 37 extending therefrom which has aninlet port 38 and an outlet port 40 communicating with the wheelcylinder fluid chamber 42. The wheel cylinder 28 has a boss 44 extendingtherefrom having an inlet port 46 and an outlet port 48 communicatingwith the lluid chamber 50. Each bosshas a flange 52 for engaging thebacking plate surfaces or faces. The wheel cylinder 28 further has aninlet port 54, communicating with a master cylinder, and a bleeder port56. The backing plate has an opening 58 into which each boss 36 and 44extend. The extent to which the bosses may be placed into the opening 58is limited by engagement of the ear 30 and the flanges S2 on fthebacking plate faces. The inlet port 38 and outlet port 4S are alignedand the inlet port 46 and the outlet port 40 are aligned. Each boss hasaligned annular notches which receive an O-ring 60 for separating thealigned ports 46 and 40 from the other aligned ports 38 and 48 and eachIboss has a shoulder therein which forms an annular notch when thebosses abut each other for receiving another O-ring 53 Which separatesthe aligned ports from the exterior of the wheel cylinders. Thus, it canbe seen the fluid communicated to the inlet nozzle 54 will travel toeach fluid chamber 42 and 50 and when it is desired to Ableed the wheelcylinder fluid chambers, the nid will pass through ports 40 and 46 andbleed port 56.

A thrust element 62 of each respective Wheel cylinder interconnects apiston 64 with the brake shoe 12 of one set of brake shoes end the brakeshoe 14 of the other set of brake shoes. Assuming rotation of the brakedrum in the direction of the arrow A, the brake shoes 12 and 14 will bethe leading brake shoes and the brake shoes 12a and 14a will be thetrailing brake shoes. Upon actuation of the wheel cylinders the thrustelement 62 will thrust the brake lining 13 of the brake shoes 12 and 14against the brake drum surface and upon engagement of the frictionlinings with the 'brake drum the shoes 12 and 14 will tend to rotate thebrake drum thereby transferring their movement to the brake shoes 12aand 14a through the struts 2i) effecting engagement of the linings ofshoes 12a and 14a with the drum 14. Upon release of the pressure in thewheel cylinders, springs 66 will urge the brake shoes to retractedposition. While a wheel cylinder having one piston for spreading onlyone shoe has been illustrated, obviously an opposed piston wheelcylinder for spreading both shoes of a set may be utilized.

The embodiment of the invention has been chosen for purposes 0fillustration, and it will be understood that it is in no way restrictiveof the invention. It is reasonably to be expected 4that those skilled inthe art may make .numerous adaptations and revisions of the inventionwithout departing from the spirit and scope of the invention andtherefore it is intended that such revisions and variations asincorporate the herein disclosed principles, will *be included withinthe following claims as equivalents thereof.

I claim:

1. In a drum brake comprising: a backing plate having an openingtherein, a pair of Wheel cylinders each having a boss thereon, each bosshaving an inlet and outlet port communicating with its respective wheelcylinder fluid chamber, one of said wheel cylinders having a hose inletport and a bleeder port communicating with its respective wheel cylinderfluid chamber, means connecting said wheel cylinders to said backingplate, said wheel cylinders being arranged on said backing plate withthe boss of each extending into said opening and abutting each other,the inlet port of one boss being generally aligned with the outlet portof `the other -boss and the outlet port of said one boss being generallyaligned with the inlet port of said other boss, a pair of annularsealing members, a pair of annular aligned depressions one on each ofthe abutting surfaces defining an annular space therebetween surroundingone of said openings on each boss, one of said sealing members beingreceived within said space formed by said aligned depressions, a pair ofannular shoulders one on each of said bosses cooperating to define anannular recess receiving the other of said sealing members, said secondsealing member engaging the wall of said backing References Cited by theExaminer UNITED STATES PATENTS 2,382,927 8/1945 Whtacre 18S-1522,496,562 Q/ 1950 Schnell 188-152 FOREIGN PATENTS 788,586 1/ 1958 GreatBritain.

MILTON BUCHLER, Primary Examiner. G. E. A. HALVOSA, Assistant Examiner.

1. IN A DRUM BRAKE COMPRISING: A BACKING PLATE HAVING AN OPENINGTHEREIN, A PAIR OF WHEEL CYLINDERS EACH HAVING A BOSS THEREON, EACH BOSSHAVING AN INLET AND OUTLET PORT COMMUNICATING WITH ITS RESPECTIVE WHEELCYLINDER FLUID CHAMBER, ONE OF SAID WHEEL CYLINDERS HAVING A HOSE INLETPORT AND A BLEEDER PORT COMMUNICATING WITH ITS RESPECTIVE WHEEL CYLINDERFLUID CHAMBER, MEANS CONNECTING SAID WHEEL CYLINDERS TO SAID BACKINGPLATE, SAID WHEEL CYLINDERS BEING ARRANGED ON SAID BACKING PLATE WITHTHE BOSS OF EACH EXTENDING INTO SAID OPENING AND ABUTTING EACH OTHER,THE INLET PORT OF ONE BOSS BEING GENERALLY ALIGNED WITH THE OUTLET PORTOF THE OTHER BOSS AND THE OUTLET PORT OF SAID ONE BOSS BEING GENERALLYALIGNED WITH THE INLET PORT OF SAID OTHER BOSS, A PAIR OF ANNULARSEALING MEMBERS, A PAIR OF ANNULAR ALIGNED DEPRESSIONS ONE ON EACH OFTHE